The High Density Z-Pinch as a Fusion Reactor

Haines, M. G.

doi:10.1007/978-1-4613-3470-5_14

Cited by 5 publications

(5 citation statements)

References 6 publications

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“…The density jump relative to the undisturbed neutral density in the neutral layer decreases during the expansion whilst the thickness of the layer increases. During the preheat phase the radius of the plasma column expands with a velocity of 8.7 ± 1.7 X 10 3 ms" 1 and does not vary with the neutral gas pressure. This is in agreement with the streak photographs.…”

Section: Resultsmentioning

confidence: 97%

“…Calculations by Haines [ 1 ] indicate that an ohmically heated Z-pinch, in pressure equilibrium with losses due to bremsstrahlung radiation and conduction to the electrodes, can satisfy the Lawson conditions. A driving current of about 1 MA sustained by a voltage of about 100 kV is required.…”

Section: Introductionmentioning

confidence: 99%

“…It has been suggested [1,3] that these plasma parameters can be achieved in a gas embedded pinch where a filamentary discharge is generated in the surrounding high pressure neutral gas. Several experiments investigating this pinch configuration have been reported [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Thus the condition for the rate of rise of the current given by Eq. ( 1) was matched to a current source with dl/dt = 1.1 X lO^A-s" 1 .…”

Section: Introductionmentioning

confidence: 99%

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Experimental and theoretical investigation of the gas embedded Z-pinch

et al. 1988

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The paper reports observations of a sub-millimetre diameter Z-pinch discharge initiated in hydrogen gas at high pressure (0.33-2 bar) and powered by a fast rising current (dI/dt ≈ 1 kA·ns−1). The conditions for heating the pinch ohmically under pressure balance are established by using a small preheat current of short duration (5 kA, 70 ns). Measurements of the radial density profiles of the electrons in the pinch and the surrounding neutral gas are presented. The peak electron temperature in the pinch is estimated from the soft X-ray emission. The observations show that during the preheat phase, when there is no equilibrium, the plasma column expands radially and drives a shock into the neutral gas. This results in an increase of the neutral gas density in a thin layer surrounding the pinch. When the main current is applied, a pinch in radial equilibrium, with a radius of about 400 μm and peak electron density on axis (2.5 × 1024 m−3 at 0.33 bar), is observed. The estimated peak electron temperature on axis (69 eV at 0.33 bar) is about twice the Bennett temperature. An increase of the line density is observed during the equilibrium. This is ascribed to a flow of neutral particles from the high density layer surrounding the pinch column. The equilibrium is destroyed by an m = 1 instability which grows from a helical perturbation on axis. The experimental results are compared with calculations based on ideal MHD stability theory, and it is shown that the existence of a centrally peaked current density profile can be inferred from the nature of the observed instabilities. An explanation is offered for the absence of the m = 0 mode, on the basis of cooling of the outer region of the plasma.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Thus the condition for the rate of rise of the current given by Eq. ( 1) was matched to a current source with dl/dt = 1.1 X lO^A-s" 1 .…”

Section: Introductionmentioning

confidence: 99%

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Experimental and theoretical investigation of the gas embedded Z-pinch

et al. 1988

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“…Bolton et al [637] considered the gas-embedded pinch at high pressure. This followed earlier proposals by Haines [638] which included employing a matrix of Z-pinches immersed in liquid lithium, and using the injection of DT gas bubbles and laser initiation. Haines and Walker [639] considered the serendipitous employment of a pressure vessel of similar design to pressurized water reactors (PWRs).…”

Section: Early Reactor Concepts For the Z-pinchmentioning

confidence: 98%

A review of the denseZ-pinch

Haines

2011

Plasma Phys. Control. Fusion

390

184

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The Z-pinch, perhaps the oldest subject in plasma physics, has achieved a remarkable renaissance in recent years, following a few decades of neglect due to its basically unstable MHD character. Using wire arrays, a significant transition at high wire number led to a great improvement in both compression and uniformity of the Z-pinch. Resulting from this the Z-accelerator at Sandia at 20 MA in 100 ns has produced a powerful, short pulse, soft x-ray source >230 TW for 4.5 ns) at a high efficiency of ∼15%. This has applications to inertial confinement fusion. Several hohlraum designs have been tested. The vacuum hohlraum has demonstrated the control of symmetry of irradiation on a capsule, while the dynamic hohlraum at a higher radiation temperature of 230 eV has compressed a capsule from 2 mm to 0.8 mm diameter with a neutron yield >3 × 10 11 thermal DD neutrons, a record for any capsule implosion. World record ion temperatures of >200 keV have recently been measured in a stainless-steel plasma designed for Kα emission at stagnation, due, it was predicted, to ion-viscous heating associated with the dissipation of fast-growing short wavelength nonlinear MHD instabilities. Direct fusion experiments using deuterium gas-puffs have yielded 3.9×10 13 neutrons with only 5% asymmetry, suggesting for the first time a mainly thermal source. The physics of wire-array implosions is a dominant theme. It is concerned with the transformation of wires to liquid-vapour expanding cores; then the generation of a surrounding plasma corona which carries most of the current, with inward flowing low magnetic Reynolds number jets correlated with axial instabilities on each wire; later an almost constant velocity, snowplough-like implosion occurs during which gaps appear in the cores, leading to stagnation on the axis, and the production of the main soft-x-ray pulse. These studies have been pursued also with smaller facilities in other laboratories around the world. At Imperial College, conical and radial wire arrays have led to highly collimated tungsten plasma jets with a Mach number of >20, allowing laboratory astrophysics experiments to be undertaken. These highlights will be underpinned in this review with the basic physics of Z-pinches including stability, kinetic effects, and finally its applications.

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